Thermal Analysis and Magnetic Properties of Lanthanum Barium Manganite Perovskite

The lanthanum manganite is the family of magnetic materials which had the magnetic properties are varied depend on the composition. This study has been carried out synthesis and characterization of thermal and magnetic properties of the lanthanum barium manganite perovskite. The perovskite material is prepared by oxides, namely La2O3, BaCO3, and MnCO3. The mixture was milled for 10h and then sintered at temperature of 1000 °C for 10h. Thermal analysis and magnetic properties are measured by differential thermal analysis (TG-DTA) and vibrating sample magnetometer (VSM), respectively. Decomposition phase of MnCO3become MnO occurred at temperatures around 390 °C with releasing in CO2. Since lanthanum manganite has a stable ion configuration, magnetic properties of these systems are built from MnO phase transformation become α-Mn2O3is arrayed anti-ferromagnetic due to the presence of lanthanum in the system. And this anti-ferromagnetic behavior occurred due to magnetic interactions between Mn3+adjacent ions through super-exchange mechanism. While lanthanum barium manganite had a less stable ion configuration, therefore magnetic properties of these systems are built from phase transformation MnO become α-Mn3O4is arrayed ferromagnetic due to the presence of lanthanum and barium in this system. The presence of lanthanum and barium trigger in the emergence of mixed-valence Mn ions, so that occur to magnetic interaction between Mn3+and Mn4+through the double-exchange mechanism. We concluded that the characteristic of magnetic properties on the lanthanum barium manganite system perovskite is affected by thermal properties, fundamental properties of raw material and the result of reaction is formed.

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Theoretical investigation on structural and magnetic properties of Mn-doped and C co-doped Zn12Se12 nanoclusters

Current Nanoscience ◽

10.2174/1573413716999200812124413 ◽

2020 ◽

Vol 16 ◽

Author(s):

Liangyan Chen ◽

Chao Fang ◽

Weihua Liu

Keyword(s):

Magnetic Properties ◽

Density Functional ◽

Theoretical Calculations ◽

Density Functional Theory Calculation ◽

Double Exchange ◽

Building Blocks ◽

Exchange Mechanism ◽

Hole State ◽

Doped Clusters ◽

Mn Doped

Background: Mn doped ZnSe low dimensional materials are attractive for different biological labels, gene silencing and dilute-magnetic device. ZnSe clusters are one of the basic building blocks of quantum dots and even clusterassembled nanodevices, Stable structures of undoped ZnSe clusters were established by previous pioneering work, and the Mn doped ZnSe clusters had been investigated, but the stable cluster in ferromagnetic state haven't been found yet. Objective: Our work mainly concentrates on Mn doped clusters (Mn2Zn10Se12) and C codoped clusters (Mn2Zn10CSe11) structure, magnetic properties through theoretical calculations. Methods: First principle density functional theory calculation with Dmol3 are used to execute all calculations. Results: Mn atoms prefer to substitute nearest neighbor Zn atom sites in rhombi part, and C atom prefers to occupy Se atom sites with shortest Mn-C bond length in Zn12Se12 nanocluster doping. Mn doped clusters (Mn2Zn10Se12) were in antiferromagnetic states and the most stable C codoped clusters (Mn2Zn10CSe11) were in ferromagnetic states. Magnetic behavior localized at the 3d orbitals of transitional metal Mn, 4p orbital of atom Se and 2p orbital of C atom. Mn2Zn10Se12 clusters were in antiferromagnetic states as the p-d hybridization introduced Mn-Mn superexchange mechanism. For the ferromagnetism of Mn2Zn10Se12 nanocluster, hole mediated double exchange mechanism introduced by C atom p-d hole state hybridization has been suggested. Conclusion: The codoping of C atom can stabilize the ferromagnetism of clusters through hole mediated double exchange mechanism, which may be meaningful for the exploring materials for cluster-assembled spin-electronic devices.

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Modification of pseudobrookite Fe1.7Mn0.3-xNixTiO5: Influence of Ni-substitution on the magnetic properties

Malaysian Journal of Fundamental and Applied Sciences ◽

10.11113/mjfas.v16n4.1758 ◽

2020 ◽

Vol 16 (4) ◽

pp. 464-468

Author(s):

Mashadi Sunandar ◽

Yosef Sarwanto ◽

Wisnu Ari Adi ◽

Yunasfi Yunasfi

Keyword(s):

Magnetic Properties ◽

Single Phase ◽

Raw Materials ◽

Double Exchange ◽

High Energy ◽

Ferromagnetic Behavior ◽

X Ray Diffraction ◽

Double Exchange Interaction ◽

Diffraction Profile ◽

Milling Equipment

In this study, the synthesis of pseudobrookite Fe1.7Mn0.3-xNixTiO5 with variations in composition (x = 0.01, 0.05, 0.1, and 0.15) using a mechanical milling technique has been performed. High purity powder of α-Fe2O3, TiO2, MnCO3, and NiO were prepared as raw materials. The mixture was milled for 5 hours using high energy milling equipment, and sintered at 1000 °C for 5 hours. The refinement result of X-ray diffraction profile shows that the all of pseudobrookite Fe1.7Mn0.3-xNixTiO5 samples have a single phase with particle size of less than 1 μm. The VSM result shows all the samples were ferromagnetic behavior. We concluded that the substitution Ni into Mn on the pseudobrookite Fe1.7Mn0.3-xNixTiO5 can change the magnetic properties of the material from paramagnetic to ferromagnetic through a mechanism of double exchange interaction.

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Photoluminescence and Magnetic Properties of Undoped and (Mn, Co) co-doped ZnO Nanoparticles

Current Nanoscience ◽

10.2174/1573413715666191010162626 ◽

2020 ◽

Vol 16 (4) ◽

pp. 655-666

Author(s):

Mona Rekaby

Keyword(s):

Magnetic Properties ◽

Zno Nanoparticles ◽

Room Temperature ◽

Magnetic Measurements ◽

Structural Defects ◽

Ferromagnetic Behavior ◽

Secondary Phases ◽

Antiferromagnetic Ordering ◽

Doped Zno ◽

Co Doped

Objective: The influence of Manganese (Mn2+) and Cobalt (Co2+) ions doping on the optical and magnetic properties of ZnO nanoparticles was studied. Methods: Nanoparticle samples of type ZnO, Zn0.97Mn0.03O, Zn0.96Mn0.03Co0.01O, Zn0.95Mn0.03 Co0.02O, Zn0.93Mn0.03Co0.04O, and Zn0.91Mn0.03Co0.06O were synthesized using the wet chemical coprecipitation method. Results: X-ray powder diffraction (XRD) patterns revealed that the prepared samples exhibited a single phase of hexagonal wurtzite structure without any existence of secondary phases. Transmission electron microscope (TEM) images clarified that Co doping at high concentrations has the ability to alter the morphologies of the samples from spherical shaped nanoparticles (NPS) to nanorods (NRs) shaped particles. The different vibrational modes of the prepared samples were analyzed through Fourier transform infrared (FTIR) measurements. The optical characteristics and structural defects of the samples were studied through Photoluminescence (PL) spectroscopy. PL results clarified that Mn2+ and Co2+ doping quenched the recombination of electron-hole pairs and enhanced the number of point defects relative to the undoped ZnO sample. Magnetic measurements were carried out at room temperature using a vibrating sample magnetometer (VSM). (Mn, Co) co-doped ZnO samples exhibited a ferromagnetic behavior coupled with paramagnetic and weak diamagnetic contributions. Conclusion: Mn2+ and Co2+ doping enhanced the room temperature Ferromagnetic (RTFM) behavior of ZnO. In addition, the signature for antiferromagnetic ordering between the Co ions was revealed. Moreover, a strong correlation between the magnetic and optical behavior of the (Mn, Co) co-doped ZnO was analyzed.

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Quantitative mapping of magnetic properties at the nanoscale with bimodal AFM

Nanoscale ◽

10.1039/d0nr08662b ◽

2021 ◽

Vol 13 (3) ◽

pp. 2026-2033

Author(s):

Victor G. Gisbert ◽

Carlos A. Amo ◽

Miriam Jaafar ◽

Agustina Asenjo ◽

Ricardo Garcia

Keyword(s):

Magnetic Properties ◽

Spatial Resolution ◽

High Spatial Resolution ◽

Magnetic Interactions ◽

Quantitative Mapping ◽

Quantitative Accuracy

We demonstrate that a force microscope operated in a bimodal configuration enables the mapping of magnetic interactions with high quantitative accuracy and high-spatial resolution (∼30 nm).

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Magnetic properties evolution with grain boundary phase transformation and their growth in Nd-Fe-Cu-Ga-B sintered magnet during post-sinter annealing process

Intermetallics ◽

10.1016/j.intermet.2021.107303 ◽

2021 ◽

Vol 137 ◽

pp. 107303

Author(s):

Song Fu ◽

Xiaolian Liu ◽

Jiaying Jin ◽

Zhiheng Zhang ◽

Yongsheng Liu ◽

...

Keyword(s):

Magnetic Properties ◽

Phase Transformation ◽

Grain Boundary ◽

Annealing Process ◽

Boundary Phase ◽

Sintered Magnet

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Effect of Sr Doping on Structure and Emittance of La1-xSrxMnO3 Smart Thermal Control Films

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.602-603.902 ◽

2014 ◽

Vol 602-603 ◽

pp. 902-905

Author(s):

Yong Jun Shen ◽

Chuan Bin Wang ◽

Ling Li ◽

Qiang Shen ◽

Lian Meng Zhang

Keyword(s):

Thin Film ◽

Smooth Surface ◽

Pulsed Laser ◽

Double Exchange ◽

Thermal Control ◽

Laser Deposition ◽

Lanthanum Manganite ◽

Infrared Emissivity ◽

Control Material ◽

Double Exchange Interaction

Sr-doped lanthanum manganite (La1-xSrxMnO3) is characteristic of thermochromic, which can act as a smart thermal control material used in the variable-emittance devices. In the present study, La1-xSrxMnO3 thin films were prepared on MgO(100) substrates by pulsed laser deposition, and the effect of Sr-doping (x = 0 ~ 0.4) on the structure and infrared emissivity was investigated. Single-phased La1-xSrxMnO3 films with (100)-orientation were obtained, which showed a dense texture with smooth surface. The ratio of Mn4+/Mn3+ in the films was increased with increasing Sr doping, leading to the enhancement in double-exchange interaction and electrical conductivity. As a result, the phase transition from metal to insulator was observed with the increasing of test temperature. For the La0.8Sr0.2MnO3 thin film, a large value of emittance (De = 0.28) was obtained, indicating good variable-emittance by appropriate Sr doping.

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The effect of pressure and alloying on half-metallicity of quaternary Heusler compounds CoMnYZ (Z = Al, Ga, and In)

Materials Science-Poland ◽

10.1515/msp-2016-0120 ◽

2016 ◽

Vol 34 (4) ◽

pp. 905-915 ◽

Cited By ~ 7

Author(s):

M. Rahmoune ◽

A. Chahed ◽

A. Amar ◽

H. Rozale ◽

A. Lakdja ◽

...

Keyword(s):

Magnetic Properties ◽

Density Functional ◽

Heusler Alloys ◽

Band Gaps ◽

Ferromagnetic Behavior ◽

Full Potential ◽

Energy Bands ◽

Half Metallicity ◽

Half Metallic ◽

Electronic And Magnetic Properties

AbstractIn this work, first-principles calculations of the structural, electronic and magnetic properties of Heusler alloys CoMnYAl, CoMnYGa and CoMnYIn are presented. The full potential linearized augmented plane waves (FP-LAPW) method based on the density functional theory (DFT) has been applied. The structural results showed that CoMnYZ (Z = Al, Ga, In) compounds in the stable structure of type 1+FM were true half-metallic (HM) ferromagnets. The minority (half-metallic) band gaps were found to be 0.51 (0.158), 0.59 (0.294), and 0.54 (0.195) eV for Z = Al, Ga, and In, respectively. The characteristics of energy bands and origin of minority band gaps were also studied. In addition, the effect of volumetric and tetragonal strain on HM character was studied. We also investigated the structural, electronic and magnetic properties of the doped Heusler alloys CoMnYGa1−xAlx, CoMnYAl1−xInx and CoMnYGa1−xInx (x = 0, 0.25, 0.5, 0.75, 1). The composition dependence of the lattice parameters obeys Vegard’s law. All alloy compositions exhibit HM ferromagnetic behavior with a high Curie temperature (TC).

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A Study on The Phase Transformation and Exchange-Coupling of (Nd0 95La0 05)9 5FebalCo5Nb2B10.5 Nanocomposites

MRS Proceedings ◽

10.1557/proc-577-209 ◽

1999 ◽

Vol 577 ◽

Author(s):

Q. Chen ◽

B. M. Ma ◽

B. Lu ◽

M. Q. Huang ◽

D. E. Laughlin

Keyword(s):

Grain Size ◽

Magnetic Properties ◽

Phase Transformation ◽

Thermal Treatment ◽

Grain Growth ◽

Exchange Coupling ◽

Phase Distribution ◽

Maximum Energy ◽

Treatment Temperature ◽

Phase Identification

ABSTRACTThe phase transformation and the exchange coupling in (Ndo095Lao005)9.5FebaICOsNb 2BI05 have been investigated. Nanocomposites were obtained by treating amorphous precursors at temperatures ranging from 650TC to 9500C for 10 minutes. The magnetic properties were characterized via the vibrating sample magnetometer (VSM). X-ray diffraction (XRD), thermomagnetic analysis (TMA), and transmission electron microscopy (TEM) were used to perform phase identification, measure grain size, and analyze phase distribution. The strength of the exchange coupling between the magnetically hard and soft phases in the corresponding nanocomposite was analyzed via the AM-versus-H plot. It was found that the remanence (Br), coercivity (Hci), and maximum energy product (BHmax) obtained were affected by the magnetic phases present as well as the grain size of constituent phases and their distribution. The optimal magnetic performance, BHm, occurred between 700°C to 750°C, where the crystallization has completed without excessive grain growth. TMA and TEM indicated that the system was composed of three phases at this point, Nd2(Fe Co) 14B, ca-Fe, and Fe3B. The exchange coupling interaction among these phases was consistently described via the AM-versus-H plot up to 750°C. The Br, Hci, and BHmax degraded severely when the thermal treatment temperature increased from 750°C. This degradation may be attributed to the grain growth of the main phases, from 45 to 68nm, and the development of precipitates, which grew from 5nm at 750°C to 12nm at 850°C. Moreover, the amount of the precipitates was found to increase with the thermal treatment temperatures. The precipitates, presumably borides, may cause a decrease in the amount of the a-Fe and Fe 3B and result in a redistribution of the Co in the nanocomposites. The increase of the Co content in the Nd 2(Fe Co) 14B may explain the increase of its Curie temperature with the thermal treatment temperatures. In this paper, we examine the impacts of these factors on the magnetic properties of (Ndo 95Lao 05)9 5FebaICosNb2B10.5 nanocomposite.

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